Fabrication of highly water-repelling paper by surface coating with stearic acid modified calcium carbonate particles and reactive biopolymers
Abstract: Cellulose paper is the most attractive green packaging material due to its recyclability, renewability, sustainability and biodegradability. In some applications, paper with a high level of water resistance is desirable to meet specific requirements in modern packaging fields. This research aimed to develop a water-repelling paper with cost-effective and nontoxic materials. Commercial precipitated calcium carbonate (PCC) particles were modified by stearic acid (SA) and incorporated with soybean oil-based binder as a water repelling coating agent. The water-repelling efficiency of the coated paper was highly dependent on the ratio of SA/PCC as well as the binder content in the coating formula. PCC particles modified with 12wt% SA were efficient in increasing the water contact angle (WCA) of the coated paper to 146° at a coating weight of 5 g/m2. The binder for the coating was synthesized with acrylated epoxidized soybean oil (AESO) through Michael addition reaction. The triglyceride structure in the polymer chain imparted good bio-degradability to the binder polymer. It was found that surface modification of PCC with stearic acid played an important role in improving the WCA of paper. A super hydrophobic paper with a WCA of 162° was fabricated with a coating formula of 60% SA-modified PCC and 40 wt% AESO-binder.